Kaisai GXP Bike Direct Installation Positive and Negative Disc Accessory for Mountain Bicycle Road Bike 40T

Feature: 1. Positive and negative disc, hard to drop chain. 2. The anode will form an oxide film on the aluminum surface, effectively protecting the aluminum alloy body. 3. Anti corrosion and anti rust, anode treatment, long term use will not fade. 4. Wonderful accessory for mountain bike, road bike. 5. 5 different type for you to choose, meet your different needs Specification: Condition: 100percent Brand New Item Type: Ceramic Bearing Rear Derailleur Pulley Material: High strength aluminum alloy + ceramic bearing Color: blackSize: 11T Diameter is about 41mm 1.6in, 13T Diameter is about 49mm 1.9inOptional: 32T, 34T, 36T, 38T, 40T Specification: use 4 5 6mm shaft guide roller Selection principle: 1. Try to choose the same size as the ori